Knife-sharpener for cloth-cutting machines.



v F. L. ROOT. KNIFE SHARPENER FDR CLOTH CUTTING MACHINES.

APPLICATION FILED NOV. 13, 1915.

Patented Mar. 28, 1916.

3 SHEETS-SHEET l.

ATTORNEKS F. L. ROOT. KNIFE SHARPENER FOR CLOTH CUTTING MACHINES.

APPLICATION FILED NOV. 13. 1915.

Patented Mar. 28, 1916.

3 SHEETS-SHEET 2.

l I l IN l/EIV TOR M1947 W E N R 0 T T A F. L. ROOT.

KNIFE SHARPENER FOR CLOTH CUTTING MACHINES.

APPLICATION FILED NOV. 13. I915.

Patented Mar. 28, 1916.

3 SHEETS-SHEET 3.

INVENTOI? A TTOR/VEK? w W M KM FRANK LESLIE ROOT, NEW YORK, N. Y., ASSIGNOR TO HJMAIMIN COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

KNIFE-SHARPENER FOR CLOTH-CUTTING MACHINES.

Specification of Letters Patent.

Patented Mar. as, 1916.

Application filed November 13, 1915. Serial No. 61,261.

To all whom itmay concern.

Be it known that I, FRANK L. Roo'r, 'a citizen of the United States, whose postoflice address is city, county, and State of a full, clear, and exact description of the in:

vention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present-invention relates primarily to improved means for sharpening the knife not in use.

of a cloth-cutting machine of the reciproeating-knife. type, whereby the knife may be well and uniformly sharpened by. a'simple manipulation. of a sharpening attachment; but, as will be understood fromthe following description, the sharpening means embodied in the attachment are of general utility and are claimed as part of my invention independently of the cloth-cutting machine.

sharpening attachment associated with a known type of reciprocating-blade cloth cutting machine, Figure 1 shows the ma- .chine and the attachment in side elevation, the attachment being shown in full lines in its sharpening position, and in dotted lines in the position which it assumes when it'is Fig. 2 shows the machine of Fig. 1 in front elevation; Fig. 3 shows on a larger'scale the grindstones and a. part of their carrier associated with a bar of the double rack bar; Fig. 4 is a section on the line 4l4 of Fig.5; Fig. 5 is a top plan view partly in section-of the sharpening attachthe front portion of the cloth cutting chine, a rack bar 2 pivoted to the attaching piece 1, a carrier 3 which 1s mounted for ment, and Fig. 6 shows a portion of the knife blade and indicates the sharpening eflect thereon of the grindstones arranged in the manner shownin the other figures.

The sharpening attachment comprises an attaching piece 1, by which it is attached to dotted lines, and out of the way when the machine is in use. I also prefer to provide the attachment, at its lower end, with an adjustable spacing foot 6 adapted to make contact with the standard, or other fixed I part, of the machine and to determine the proper position of the sharpening attachment with respect to the knife blade when the attachment is in use.

By.referring to Figs. 3 to 5, inclusive, it wlll be seen that the rack bar 2 has two internal racks facing toward one another, the carrier 3 .is mounted for reciprocation on the rack bar and carries the stub shafts 7 which support the grindstones 4 and which carry pinions 8 meshing with racks of the rack bar, so that when the carrier is reciprocated on the rack bar the grindstones will be rotated 1n opposite directions, as indicated by the-arrows in Fig. 3. In the particular embodiment of the invention here shown the grindstones are of cylindrical shape and the stub shafts 7 are inclined upwardly from the horizontal and outwardly from the plane of the knife blade so that the grinding surfaces are inclined upwardly, and outwardly from the plane of the knife blade.

In using the grinder attachment it is brought from the dotted line position to the full line position as shown in the drawings, the foot 6 having preferably been set, for the particular machine, to hold the rack bar 2 parallel with the edge of the knife. The sharpening'movement which the operator will find most convenient will consist of a downward sweep during which the grindstones are brought into contact with and grind the edge of the knife, a slight outward movement of the attachment at the bottom 'of the sweep, and an upward movement without contact with the knife. In either case, with the arrangement shown. there will be produced on the knife an uwardly cutting edge, as indicated in Fig.1 and in Fig. 6, the object of the upward inclination of the grinding surfaces being to give the proper inclination to this edge. If it is desired to produce on the knife a down cutting edge, then the stones should be inclined downwa-rdly and outwardly, that is to say, the carrier 3 should be reversed on the rack 2. In order that this may'readily be accom plished, the lower end plate of the'rack is fastened on by removable screws as indicated in Fig. 4, so that it is only necessary to remove these screws and the end plate to remove and reverse the carrier and then 60 into sharpening relation with the edge of the sharpener to produce an edge which will replace the endplate in order to adapt the which has a front cutting edge and also a. bottom cutting edge, ,as indicated in Figs.

Y 1 and .6, and itis likewise customary to sharpen the front edge of the knife so that it, as well as the bottom edge of the knife,

. will cut on the down stroke. I have discov-. ered that the smoothness and rapidityof the cutting operation can be increased by so sharpening'the front edge of the knife that it will out on the up stroke, while the bottom edge. of the knife cuts on the down stroke. With such an arrangement the ac.- tion seems to be that the lower layers of cloth press forward uncut beneath the knife on the up stroke and in the succeedingdown stroke are cut y the bottom edge of the knife; and in this Way the knife cutsmore efi'ectively and more smoothly than when the cutting operation is confined to the down stroke. Such a sharpening of the knife blade involves the use of efi'ective mechanism to prevent the lifting up of the to layers of cloth on the up stroke of the ife. Such. an efiective arrangement is disclosed in the United States patent application of David S. Maimin, Serial No. 54,067, filed October a, 1915, and I intend to use such arrangement in connection with my present invention. Fig. 2 of the drawings shows a two-part stripper-foot of that application at 10, and it will be understood that when the parts of the stripper-foot are brought into position above the lays of cloth they are effective to hold down the cloth even when the knife iscutting on the up stroke. I do not wish it to be understood that this feature of my present invention is limited to use with the particular stripper-foot here'illustrated,

since it is clear that the only necessary thing is that. the stripper-foot should be capable of holding down the cloth when the knife is cutting on the up stroke.

WhatI claim is: I

LA cloth-cutting machine having a reciprocating knife and a knife sharpening at-- tachment, comprising a guide rack in ad- Vance of the cutting edge of said knife, a carrier reciprocable on the guide rack, stub shafts rotatably mounted in the. carrier and supporting the grindstones, and pinions on the stub shafts meshing with the rack where- A by when the carrieris reciprocated on the guide rack the grindstones will be rotated, said attachment being so mounted on theme chine that the grindstones may be brought knife. i

2. A cloth-cutting .machine having a reciprocating knife and a knife-sharpening" attachment comprising a guide having -a' arrears pair of racks-spaced apart and facing toward one another, a carrier reciprocable on the guide, stub shafts rotatably mounted in the carrier and supporting grindstones, and pinions: on the 'stub' shafts each meshing with one of the racks'so that'when the carrier is-reciprocated on the guide the grindstones'will .be rotated in opposite direction, said attachment being so mounted on the machine that the grindstones may be brought into sharpeningrelation with the edge of the knife. v

3. A cloth-cutting machine having areciprocatihg knife and .a knife sharpening 1 attachment comprising aguide pivoted to the frame of the machine in front of the knife, acarrier reciprocableon the guide and carrying grindstonesi arranged to make simultaneous contact with the two sides of the edge of the knife when the guide is brought into substantial parallelism with the front edge of the lmife, .coiiperating driving elements on the guide and grindstones making guiding engagement to rotate the grindstones in contact with the edgeof the knife as the carrier is reciprocated on. the guide, and an adjustable positioning.

stop on the attachment arranged to engage a part of the machine to fix the attachment l in such sharpening relation.

4. A cloth-cutting machine having a reciprocating knife and a". knife-sharpening attachmentcomprising a guide rack in advance of the cutting edge of said knife, a

carrier reciprocable on the guide rack, stub shaftsrotatably mounted in the carrier and supporting grindstones having cylindrical grinding surfaces, and pinions on the stub shafts meshing with the rack, whereby when the carrier is reciprocated on the-guide rack,

the grindstones will be rotated, said attachment being so mounted on the machine that the grindstones may be'brought into sharpening relation with the edge of the knife, Y

the stub shafts being so set in the carrier that when the attachment is so positioned the stones will extend angularly lengthwise of and outwardly from the cutting edge of theknife.

v5. A cloth-cutting machine having a reciprocating knife and a knife-sharpening attachment comprising a guide separate from said knife and provided'with a toothed rack, a carrier reciprocable on the guide, stub shafts rotatably mounted in the carrier and supporting grindstones having cylindrical grinding surfaces, and-pinions on the stub shafts meshing with the rack, whereby when the carrier is reciprocated on the guide the grindstones Wlll be rotated, said attachment being so mounted'on the machine that the grindstones may be brought into sharpening relation with the edge of the knife 4 so that when theattachment is so positioned the grindstones will extend at an angle up- Wardly with respect to and outwardly from the cutting edge of the knife.

6. A cloth-cutting machine having a reciprocating knife and a knife-sharpening attachment comprising a guide, a carrier reciprocable and reversible on the guide and carrying grindstones having their grinding surfaces extending angularly lengthwise of and outwardly with respect to the longitudinal axis of. the guide, the attachment being so mounted on the machine that the grindstones may be brought into sharpening relation with the edge of the knife, whereby the knife may be sharpened to cut on the down stroke or on the up stroke by reversing'the carrier on the guide.

7. A cloth-cutting machine having a reciprocating knife and a knife-sharpening attachment comprising a guide rack, a carrier reciprocable and reversible on the guide rack, s'tub shafts rotatably mounted in the carrier and supporting grindstones, and pinions on the stub shafts adapted to mesh with the rack in either position of reversal of the carrier thereon, the grinding surfaces of the stones extending angularly lengthwise of and outwardly from the longitudinal axis of the guide rack, whereby the knife may be sharpened to cut on the down stroke or on the up stroke by reciprocating the carrier, in the desired osition of reversal, with the stones in grlnding relation to the knife edge.

8. A knife-sharpening device comprising a guide adapted to be positioned in substantial parallelism with the edge of a knife to be sharpened, a carrier reciprocable on the guide and carrying grindstones arranged to make simultaneous contact with the two sides of the edge of the knife, and cooperating driving elements on the guide and grindstones making driving engagement to rotate the grindstones in contact with the edge of the knife as the carrier is reciprocated on the guide. a

9. A knife-sharpening device comprising a guide adapted to be positioned in substantial parallelism with the edge of a knife to be sharpened, a carrier reciprocable on the guide and carrying grindstones arranged to make simultaneous contact with the two &

sides of the edge of the knife, and cooperatlng driving elements on the guide and grindstones making driving engagement to of the guide.

10. A knife-sharpening device comprising a guide rack separate from said knife and in advance of the cutting edge thereof, a carrier reciprocable on the guide rack, stub shafts rotatably mounted in the carrier and supporting grindstones, and pinions on the stub shafts meshing with the rack, whereby when the carrier is reciprocated on the guide rack, the grindstones will be rotated.

11. A knife-sharpening device comprising a guide having a pair of racks spaced apart and facing toward one another, a carrier reciprocable on the guide, stub shafts rotatably mounted in the carrier and supporting grindstones, and pinions on the stub shafts each meshing with one of the racks so that when the carrier is reciprocated on the guide the grindstones will be rotated in opposite directions.

12. A knife-sharpening device comprising a guide rack, a carrier reciprocable on the guide rack, stub shafts rotatably mounted in the carrier and supporting grindstones, and pinions on the stub shafts meshing with the rack, whereby when the carrier is reciprocated on the guide rack, the grindstones will be rotated, the said grindstones having cylindrical grinding surfaces and the said stub shafts being so mounted in the carrier that the grindstones will extend angularly lengthwise of and outwardly with respect to the longitudinal axis of the guide rack.

13. A cloth-cutting machine having a reciprocating blade with a front cutting edge and a bottom cutting edge, the said front cutting edge being sharpened to out most effectively on the up stroke whereby the bottom edge cuts on the down stroke and the front edge cuts on the. up stroke.

In testimony whereof I affix my signature:

FRANK LESLIE ROOT. 

